Transceiver calibrations at silent periods

1. A method of wireless communication at a first wireless device, comprising:

transmitting or receiving sidelink communication with a second wireless device during an active period; and

performing at least one of a direct current (DC) offset calibration or an in-phase quadrature (IQ) imbalance calibration for the sidelink communication during a periodic silent period for the sidelink communication.

2. The method of claim 1 , wherein the periodic silent period comprises at least one symbol of a subframe.

3. The method of claim 1 , wherein the periodic silent period comprises at least a last symbol of a subframe.

4. The method of claim 1 , wherein the first wireless device communicates with the second wireless device based on at least one of vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V), or other device-to-device (D2D) communication.

5. The method of claim 1 , further comprising:

selecting a gain state to be calibrated during the periodic silent period;

performing a measurement of a DC for the selected gain state during the periodic silent period; and

updating a DC measurement for the selected gain state.

6. The method of claim 5 , wherein selecting the gain state to be calibrated during the periodic silent period includes selecting the gain state based on a time since a previous measurement of the gain state.

7. The method of claim 6 , wherein selecting the gain state to be calibrated during the periodic silent period includes selecting a first gain state having an older measurement than a second gain state.

8. The method of claim 5 , wherein selecting the gain state to be calibrated during the periodic silent period includes selecting an untrained gain state to be calibrated during the periodic silent period.

9. The method of claim 5 , wherein the DC measurement for the selected gain state when a signal power is less than or equal to a threshold, the method further comprising:

discarding the measurement when the measurement comprises the signal power above the threshold.

10. The method of claim 1 , wherein the first wireless device transmits during the active period, the method further comprising:

switching from a transmission mode to a reception mode prior to performing the at least one of the DC offset calibration or the IQ imbalance calibration during the periodic silent period.

11. The method of claim 1 , wherein the first wireless device transmits during the active period, the method further comprising:

transmitting a transmission below a transmission power level threshold during the periodic silent period; and

using a receiver of the first wireless device to measure the transmission as part of performing the at least one of the DC offset calibration or the IQ imbalance calibration.

12. The method of claim 1 , wherein the at least one of the DC offset calibration or the IQ imbalance calibration comprises a loopback calibration.

13. The method of claim 1 , wherein the first wireless device is a first UE, and the second wireless device is a second UE.

14. The method of claim 1 , further comprising:

transmitting or receiving the sidelink communication after the periodic silent period based on the at least one of the DC offset calibration or the IQ imbalance calibration performed during the periodic silent period.

15. An apparatus for wireless communication at a first wireless device, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

transmit or receive sidelink communication with a second wireless device during an active period; and

perform at least one of a direct current (DC) offset calibration or an in-phase quadrature (IQ) imbalance calibration for the sidelink communication during a periodic silent period for the sidelink communication.

16. The apparatus of claim 15 , wherein the periodic silent period comprises at least one symbol of a subframe.

17. The apparatus of claim 15 , wherein the periodic silent period comprises a las symbol of a subframe.

18. The apparatus of claim 15 , wherein the first wireless device communicates with the second wireless device based on at least one of vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V), or other device-to-device (D2D) communication.

19. The apparatus of claim 15 , wherein the at least one processor is further configured to:

select a gain state to be calibrated during the periodic silent period;

perform a measurement of a DC for the selected gain state during the periodic silent period; and

update a DC measurement for the selected gain state.

20. The apparatus of claim 19 , wherein to select the gain state to be calibrated during the periodic silent period, the at least one processor is configured to select an untrained gain state or an older gain state having an older measurement than another gain state.

21. The apparatus of claim 19 , wherein the at least one processor is further configured to:

update the DC measurement for the selected gain state when a signal power is less than or equal to a threshold; and

discard the measurement when the measurement comprises the signal power above the threshold.

22. The apparatus of claim 15 , wherein the at least one processor is further configured to:

switch from a transmission mode for the active period to a reception mode in order to perform the at least one of the DC offset calibration or the IQ imbalance calibration during the periodic silent period.

23. The apparatus of claim 15 , wherein the at least one processor is further configured to:

transmit a transmission below a transmission power level threshold during the periodic silent period; and

use a receiver of the first wireless device to measure the transmission as part of performing the at least one of the DC offset calibration or the IQ imbalance calibration.

24. The apparatus of claim 15 , wherein the at least one of the DC offset calibration or the IQ imbalance calibration comprises a loopback calibration.

25. An apparatus for wireless communication at a first wireless device, comprising:

means for transmitting or receiving sidelink communication with a second wireless device during an active period; and

means for performing at least one of a direct current (DC) offset calibration or an in-phase quadrature (IQ) imbalance calibration for the sidelink communication during a periodic silent period for the sidelink communication.

26. The apparatus of claim 25 , wherein the periodic silent period comprises a last symbol of a subframe.

27. The apparatus of claim 25 , further comprising:

means for selecting a gain state to be calibrated during the periodic silent period, the gain state being an untrained gain state or an older gain state having an older measurement than another gain state;

means for performing a measurement of a DC for the selected gain state during the periodic silent period; and

means for updating a DC measurement for the selected gain state.

28. The apparatus of claim 27 , wherein the means for updating the DC measurement are configured to update the DC measurement for the selected gain state when a signal power is less than or equal to a threshold, the apparatus further comprising:

means for discarding the measurement when the measurement comprises the signal power above the threshold.

29. The apparatus of claim 25 , further comprising:

means for switching from a transmission mode for the active period to a reception mode in order to perform the at least one of the DC offset calibration or the IQ imbalance calibration during the periodic silent period.

30. The apparatus of claim 25 , further comprising:

means for transmitting a transmission below a transmission power level threshold during the periodic silent period; and

means for using a receiver of the first wireless device to measure the transmission as part of performing the at least one of the DC offset calibration or the IQ imbalance calibration.

31. A non-transitory computer-readable medium storing computer executable code for wireless communication at a first wireless device, the code when executed by a processor cause the processor to:

transmit or receive sidelink communication with a second wireless device during an active period; and

perform at least one of a direct current (DC) offset calibration or an in-phase quadrature (IQ) imbalance calibration for the sidelink communication during a periodic silent period for the sidelink communication.

32. The method of claim 1 , wherein the transmitting or receiving the sidelink communication with the second wireless device during the active period includes transmitting the sidelink communication with the second wireless device during the active period.

33. The method of claim 1 , wherein the transmitting or receiving the sidelink communication with the second wireless device during the active period includes receiving the sidelink communication with the second wireless device during the active period.

34. The method of claim 1 , wherein the first wireless device performs the DC offset calibration for the sidelink communication during the periodic silent period for the sidelink communication.

35. The method of claim 1 , wherein the first wireless device performs the IQ imbalance calibration for the sidelink communication during the periodic silent period for the sidelink communication.

36. The method of claim 10 , wherein the first wireless device switches from the transmission mode to the reception mode prior to performing the DC offset calibration during the periodic silent period.

37. The method of claim 10 , wherein the first wireless device switches from the transmission mode to the reception mode prior to performing the IQ imbalance calibration during the periodic silent period.

38. The method of claim 11 , wherein the first wireless device uses the receiver of the first wireless device to measure the transmission as part of performing the DC offset calibration the IQ imbalance calibration.

39. The method of claim 11 , wherein the first wireless device uses the receiver of the first wireless device to measure the transmission as part of performing the IQ imbalance calibration.

40. The method of claim 12 , wherein the DC offset calibration comprises the loopback calibration.

41. The method of claim 12 , wherein the IQ imbalance calibration comprises the loopback calibration.

42. The method of claim 1 , wherein the first wireless device is a first UE, and the second wireless device is a second UE.

43. The apparatus of claim 15 , wherein the at least one processor is further configured to:

transmit or receive the sidelink communication after the periodic silent period based on the at least one of the DC offset calibration or the IQ imbalance calibration performed during the periodic silent period.

44. The apparatus of claim 19 , wherein to select the gain state to be calibrated during the periodic silent period, the at least one processor is configured to select the gain state based on a time since a previous measurement of the gain state.

45. The apparatus of claim 44 , wherein to select the gain state to be calibrated during the periodic silent period, the at least one processor is configured to select a first gain state having an older measurement than a second gain state.

46. The apparatus of claim 15 , wherein the at least one processor is configured to transmit the sidelink communication with the second wireless device during the active period.

47. The apparatus of claim 15 , wherein the at least one processor is configured to receive the sidelink communication with the second wireless device during the active period.

48. The apparatus of claim 15 , wherein the at least one processor is configured to perform the DC offset calibration for the sidelink communication during the periodic silent period for the sidelink communication.

49. The apparatus of claim 15 , wherein the at least one processor is configured to perform the IQ imbalance calibration for the sidelink communication during the periodic silent period for the sidelink communication.

50. The apparatus of claim 22 , wherein the the at least one processor is configured to switch from the transmission mode to the reception mode prior to the DC offset calibration during the periodic silent period.

51. The apparatus of claim 22 , wherein the at least one processor is configured to switch from the transmission mode to the reception mode prior to the IQ imbalance calibration during the periodic silent period.

52. The apparatus of claim 23 , wherein the at least one processor is further configured to use the receiver of the first wireless device to measure the transmission as part of performing the DC offset calibration the IQ imbalance calibration.

53. The apparatus of claim 23 , wherein the at least one processor is configured to use the receiver of the first wireless device to measure the transmission as part of performing the IQ imbalance calibration.

54. The apparatus of claim 24 , wherein the DC offset calibration comprises the loopback calibration.

55. The apparatus of claim 24 , wherein the IQ imbalance calibration comprises the loopback calibration.

56. The apparatus of claim 15 , further comprising:

at least one antenna coupled to the at least one processor.

57. The apparatus of claim 25 , wherein the means for transmitting or receiving the sidelink communication with the second wireless device during the active period are configured to transmit the sidelink communication with the second wireless device during the active period.

58. The apparatus of claim 25 , wherein the means for transmitting or receiving the sidelink communication with the second wireless device during the active period are configured to receive the sidelink communication with the second wireless device during the active period.

59. The apparatus of claim 25 , wherein the means for performing are configured to perform the DC offset calibration for the sidelink communication during the periodic silent period for the sidelink communication.

60. The apparatus of claim 25 , wherein the means for performing are configured to perform the IQ imbalance calibration for the sidelink communication during the periodic silent period for the sidelink communication.

61. The non-transitory computer-readable medium of claim 31 , wherein the code, when executed by the processor, further causes the processor to:

select a gain state to be calibrated during the periodic silent period;

perform a measurement of a DC for the selected gain state during the periodic silent period; and

update a DC measurement for the selected gain state.

62. The non-transitory computer-readable medium of claim 61 , wherein selecting the gain state to be calibrated during the periodic silent period includes selecting an untrained gain state to be calibrated during the periodic silent period.

63. The non-transitory computer-readable medium of claim 61 , wherein the code, when executed by the processor causes the processor to:

transmit the sidelink communication with the second wireless device during the active period.

64. The non-transitory computer-readable medium of claim 61 , wherein the code, when executed by the processor causes the processor to:

receive the sidelink communication with the second wireless device during the active period.

65. The non-transitory computer-readable medium of claim 61 , wherein the code, when executed by the processor causes the processor to:

perform the DC offset calibration for the sidelink communication during the periodic silent period for the sidelink communication.

66. The non-transitory computer-readable medium of claim 61 , wherein the code, when executed by the processor causes the processor to:

perform the IQ imbalance calibration for the sidelink communication during the periodic silent period for the sidelink communication.